Frames of this type, e.g. as known from U.S. Pat. No. 3,723,823, are of generally prismatic configuration and comprise two substantially rectangular end walls interconnected at their corners by four elongate cross-members with confronting surfaces lying in two parallel planes. The coplanar surfaces of each pair of cross-members support a set of guide elements which form track channels designed to receive opposite edges of a printed-circuit board or other article to be inserted therebetween. Obviously, these confronting supporting surfaces must be spaced apart by a distance exceeding the dimension of the articles in a direction perpendicular thereto, i.e. their height in case the supporting surfaces are substantially horizontal.
In such a frame it is, of course, necessary to prevent the untimely separation of any inserted article from its guide elements. Various means have heretofore been proposed for this purpose, including the use of guide bars with ribs arranged in a herringbone pattern, as disclosed in commonly owned U.S. Pat. No. 4,098,046, or the provision of a spring-loaded detent for latching adjoining container walls to each other, as described in Italian utility model No. 119,387.